Messages in this thread | | | Date | Thu, 26 Jan 2012 21:15:16 -0800 (PST) | From | Dan Magenheimer <> | Subject | RE: [PATCH] mm: implement WasActive page flag (for improving cleancache) |
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> From: Rik van Riel [mailto:riel@redhat.com] > Subject: Re: [PATCH] mm: implement WasActive page flag (for improving cleancache) > > On 01/26/2012 09:43 PM, Dan Magenheimer wrote: > > > Maybe the Active page bit could be overloaded with some minor > > rewriting? IOW, perhaps the Active bit could be ignored when > > the page is moved to the inactive LRU? (Confusing I know, but I am > > just brainstorming...) > > The PG_referenced bit is already overloaded. We keep > the bit set when we move a page from the active to the > inactive list, so a page that was previously active > only needs to be referenced once to become active again. > > The LRU bits (PG_lru, PG_active, etc) are needed to > figure out which LRU list the page is on. I don't > think we can overload those...
I suspected that was true, but was just brainstorming. Thanks for confirming.
Are there any other page bits that are dont-care when a page is on an LRU list?
I'd also be interested in your/RedHat's opinion on the 64-bit vs 32-bit market. Will RHEL7 even support 32-bit?
Dan
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